wcs: add customisation blocks to tracking code input cell (#40649)

combo/apps/wcs/templates/combo/wcs/tracking_code_input.html

@@ -4,7 +4,10 @@
  {% block title %}
  <h2>{% trans 'Tracking Code' %}</h2>
  {% endblock %}
+ <div>
+ {% block form-pre %}{% endblock %}
  <form data-wcs-url="{{ url }}" method="post" action="{{ site_base }}{% url 'wcs-tracking-code' %}">
+  {% block form-top %}
   {% block intro-text %}
   <p>
     {% blocktrans %}
@@ -14,6 +17,7 @@
     {% endblocktrans %}
   </p>
   {% endblock %}
+  {% endblock %}
   <input id="_cell_url_{{ cell.id }}" name="url" value="" type="hidden"/>
   <input name="cell" value="{{ cell.id }}" type="hidden"/>
   <div id="_cell_error_{{ cell.id }}" class="errornotice" style="display: none">
@@ -29,6 +33,9 @@
     }
   });
   </script>
+  {% block form-bottom %}{% endblock %}
  </form>
+ {% block form-post %}{% endblock %}
+ </div>
 </div>
 {% endblock %}